Optical cables are widely used for ultrahigh communication networks due to its low loss and large bandwidth in comparison to copper wires. However, optical cables have somewhat low reliability due to inferior mechanical properties in comparison to copper wires. In other words, optical cables are easily cut in comparison to copper wires and when bent beyond a certain angle, does not allow for communication. Therefore, when a service provider who constructed an optical communication network finds a disorder with the optical cable, he/she quickly checks to find the location of the disorder and puts workers at the location to recover the optical line.
Meanwhile, a technique of checking a disorder of an optical line by using an optical measurement instrument has been disclosed. In detail, the optical measurement instrument delivers OTDR (Optical Time Domain Reflectometer) pulses to a plurality of optical channel service units connected to a distribution unit, and analyzes a plurality of OTDR pulses (namely, a pulse pattern), which are reflected by the plurality of optical channel service units and then consecutively return, to inspect a disorder of each line.
However, even though a disorder of a specific OTDR pulse signal may be checked by analyzing a plurality of OTDR pulses obtained through the optical measurement instrument, it is impossible to specify which individual optical line receives an individual OTDR pulse. In other words, it is impossible to identify an optical channel service unit by which each of the plurality of OTDR pulses received through the optical measurement instrument is reflected.
Workers may, of course, check a final length of an extended optical line of each optical channel service unit and then identify an individual optical line of an OTDR pulse where the disorder status was found, with reference to the information about the plurality of checked lengths. However, this method requires manual work in order to check the length of an optical line, which also consumes a lot of labor costs.
Meanwhile, the OTDR pulse pattern showing a plurality of OTDR pulses exhibits pulses consecutively according to length. Here, pulses returning from a plurality of optical channel service units located at identical or similar distances based on the optical measurement instrument may be shown in the OTDR pulse pattern as being combined in a single waveform. In other words, a plurality of pulses returning from optical lines with identical or similar lengths are combined into a single pulse, and the combined pulse is shown in the OTDR pulse pattern.
In the case a plurality of pulses returning from optical lines located at identical or similar lengths are combined in a single pulse, the optical line monitoring system may not distinguish each optical line with regard to overlapping pulses in the OTDR pulse pattern. Further, in the case a disorder occurs at a specific optical line among the plurality of optical lines via which the overlapping pulses pass, the optical line monitoring system may not accurately identify an optical line where the disorder occurs, which may delay actions to cope with the disorder.